What is the role of MitraClip (mitral clip) in treating primary and secondary Mitral Regurgitation (MR)?

MitraClip in Primary and Secondary Mitral Regurgitation

For primary MR, surgical mitral valve repair remains the gold standard, with MitraClip reserved for symptomatic patients at prohibitive surgical risk; for secondary MR, MitraClip is indicated for symptomatic patients with severe MR (LVEF 20-50%, LVESD <70mm) who remain symptomatic despite optimal medical therapy. 1

Primary Mitral Regurgitation

First-Line Treatment

• Surgical mitral valve repair is the preferred treatment for severe primary MR with unanimous guideline agreement 1
• Surgery is indicated for symptomatic chronic primary MR or asymptomatic patients with LVEF ≤60% and/or LVESD ≥40mm 1
• Surgical repair should be prioritized over valve replacement when a durable repair can be achieved 1

MitraClip Indications in Primary MR

MitraClip is indicated only for highly selected primary MR patients who cannot undergo surgery: 1

• Symptomatic patients (NYHA class III-IV) with severe (3+ or 4+) primary degenerative MR 1
• Prohibitive surgical risk due to severe comorbidities 1
• Favorable anatomy for the repair procedure 1
• Reasonable life expectancy despite optimal guideline-directed medical therapy 1

Critical Limitations in Primary MR

• MitraClip is contraindicated when leaflets are restricted in both systole and diastole (Carpentier IIIA motion, such as rheumatic or radiation heart disease) because it would cause mitral stenosis 1
• Residual MR rates are significantly higher with MitraClip compared to surgery (43.1% vs 5.4% at discharge; 66.7% vs 33.3% at 1 year) 2
• Reintervention rates are higher with MitraClip (87.5% freedom from reintervention at 1 year vs 100% for surgery) 2

Secondary Mitral Regurgitation

Foundation of Treatment

Guideline-directed medical therapy (GDMT) is the cornerstone of secondary MR management and must be optimized before considering any intervention: 1

• ACE inhibitors or ARBs 1
• Beta blockers 1
• Aldosterone antagonists 1
• Cardiac resynchronization therapy (CRT) when appropriate 1
• Coronary revascularization if ischemic etiology 1

MitraClip Indications in Secondary MR

MitraClip is indicated for patients meeting ALL of the following criteria: 1

• Severe secondary MR (3+ or 4+) that persists after optimization of GDMT 1
• LVEF between 20% and 50% 1
• LV end-systolic diameter <70mm 1
• Symptomatic despite maximally tolerated GDMT as verified by a heart failure specialist 1
• Evaluation and approval by a multidisciplinary heart team experienced in heart failure and mitral valve disease 1

Evidence Base: COAPT vs MITRA-FR

The divergent results of these landmark trials highlight critical patient selection factors: 1

COAPT (positive results):

• Demonstrated 47% reduction in heart failure hospitalizations 1
• Showed 38% reduction in all-cause mortality at 24 months 1
• Patients had more severe MR (higher effective regurgitant orifice areas) 1
• Patients had less LV remodeling (lower LV end-diastolic volumes) 1
• Required verified maximally tolerated GDMT by heart failure specialist 1
• Conducted in comprehensive heart valve centers with prior MitraClip experience 1

MITRA-FR (neutral results):

• No difference in death or heart failure hospitalizations at 12 months 1
• Patients had less severe MR relative to LV size 1
• More variable heart failure medication use 1
• Higher rates of residual MR 1

Surgical Considerations in Secondary MR

• Surgery for secondary MR has NOT been shown to improve mortality despite improving functional outcomes and quality of life in selected patients 1
• Surgery is reasonable when coronary artery bypass grafting is indicated 1
• Surgery may be considered for symptomatic patients despite optimal GDMT, but evidence is limited 1

Diagnostic Requirements

Severity Assessment

Severe MR is defined by integration of multiple echocardiographic parameters: 1

• Vena contracta ≥7mm 1
• Effective regurgitant orifice area (EROA) ≥0.4 cm² for primary MR 1
• EROA ≥0.2 cm² for secondary MR 1
• Regurgitant volume ≥60 mL/beat for primary MR 1
• Regurgitant volume ≥30 mL/beat for secondary MR 1
• Regurgitant fraction ≥50% 1

Imaging Modalities

• Transthoracic echocardiography is fundamental for diagnosis 1
• Transesophageal echocardiography is required for pre-procedural planning, intraoperative imaging, and post-intervention assessment 1
• Exercise testing or stress echocardiography is important in asymptomatic patients to unmask symptoms 1

Common Pitfalls

Patient Selection Errors:

• Attempting MitraClip in primary MR patients who are suitable surgical candidates—this compromises outcomes and may complicate future surgery 2, 3
• Proceeding with MitraClip in secondary MR before optimizing GDMT—this was a key difference between COAPT and MITRA-FR 1
• Using MitraClip in patients with excessive LV dilatation (LVESD >70mm) where outcomes are poor 1

Technical Considerations:

• Prior MitraClip therapy can complicate subsequent surgical repair and may necessitate valve replacement instead of repair 3
• MitraClip should not be used when leaflet restriction would result in mitral stenosis 1
• Residual MR after MitraClip is common and associated with worse outcomes 2